Process of revivifying spent filtering materials



's. HILLER n Pnoczss oF REvIvIFYING sPENT FILTERINGMATERIALS Filed Dec. 21. 119245 Sept. 7 ,-1926. 1,598,967

.20 operations.

Patented Sept. 7, 1.926.

-. UNITED- STAT-as l h 1,598,967' PATENT. OFFICE.

STANLEY KILLER, F

sAN FRANCISCO, CALIFORNIA, AssIeNon To STANLEY HILLEF.,

INC., oF sAN FaANCIsCo, CALIFORNIA.

FnocEss vor' nEvIvIFYING sFENT FILTERING MATERIALS.. v

Application tiled December 21, 19523. Serial 682,062.

The present invention relates to animproved process for revivifylng spent filtering materials, such for example as are used 1n filtering operations in sugar, oil and like 8 industries. .The present application is a continuation in part of applicationSerial No. 488,251, filed July 28, 1925, and contains all of the subject'matter of thesaid application together With additional and more 10 specificv details regarding `the invention as originally set lforth in said application.

More particularly theinvention relates to a process of revivifying and reactivating liltering materials, for example, such as kieselguhr, fullers earth, asbestosand the like, the pores or cells .of which have become clogged withV impurities from filtering or bleaching operations to such an extent as to be substantially useless in further filtering Although adapted'for use in a batch process, in the preferred embodiment ofthe 'invention, the process i's continuous. be-understood however, that the invention is not limited to a continuous process.

' Broadly the process comprises initiating combustion of the combustible andcarbona- 'Y ceous materials contained in the spent ma-v terials bythe application of heat, and when the carbonaceous material is ignited, propagating combustion or burning out 'thereof by causing and allowing a combustion sulpporting gas to intimately contact with the ignited mass.

`JThe degree of removal of carbonaceous material from the pores of the filtering material is controlled and regulated by .regulating the supplyrof combustion supporting fluid to the ignited mass. In this manner the 40 porosity of the reviyilied product is controlled and brought tol a desired degree. Fine and coarse filtering material may be in this manner produced, depending on the degree of removal attained in the pores and cells. It will be understood that the burning out or removal may be carried to completion if desired,.or may be merely partial.

, The finer grades, or those in which removal is merely partial, are valuable in filtering 5.0 operations where a bleaching effect is desired, and may be used as an aid to, or even to replace bleaching filters.

As the process is carried out, therefusc, organic matter, and carbonaceous material u in ther pores are firstignited by the applica- It is 'to tion of heat, preferably by the application of a direct ame, and after ignition has been effected, further combustionis caused land propagated though the mass by contacting themass with a'current of air. Experimentatlon has shown that in order to propagate combustion, the currentcf air must be preheated 'at least to .thev temperature of ignition of the mass before contact, otherwise the mass is cooled andcombustion .will not l spread or be propagated through the mass.

In plants or establishments where great y quantitiesoflltering materials are used, the

rapidity with which the process may be carignition isy also relied upon to preheat and dry the ma'ss sufficiently to permit ignition. The preheating may be carried to the point of carbonizing the organic and refuse matter in the pores and cells of the mass.

To further expedite'the handling of the material and to reduce operating costs, the

process is adapted for continuous operation,

.and this is the preferred, but not the only manner of carrying out the process. 'In the continuous embodiment. hereinafter disclosed. the spent material is subjected to a drying and preheating operation prior to ignition, Eind all of the steps are continuousl)1 carried out. The removal of the carbonaceous materials by burning out occurs in e. rotary kiln in which a down draft, parallel to and in the direction of' movementof the igniter mass is induced.

The figure of the drawing represents substantially in diagram the essential details and arrangement-of a form of apparatus as used commercially to carry out the proces.; of the invention.

It will of course be understood that the mechanical details of the apparatus form no part of fthe invention', and a wide choice may be had of well known forms'of the dry; er, kiln, furnaces, conveyors, fans, and all "of the mechanical units, by those skilled in the art, without departing in any'way from the :scope and spirit of the invent-ion. The

4the discharge end so that the materials will feed to the left in the ligure at a suitable rate whichmay vary'widely and is finallyV discharged into chamber 3 and falls by gravity between Crusher rolls 4 which in turn are driven by suitable driving'means and are arranged to crush any lumps or balls of the material which mayhave formed in preheater 2. Having passed through the crusher rolls 4, thematerials are fed. throughl a feed chute 5 to a rotarytkiln 6. Kiln 6 is given a downward pitch and is rotatedcontinuouslyby suitable driving means so that the material will pass therethrough at a` suitable rate and finally discharges into a conveyor 7 which 1s driven by suitable means in 'a manner to carry the revivified material away from the apparatus to a mixer (not shown) where it is mixed to be again used for filtermg. .Part of `the reviviiied material is discharged from conveyor 7 into a lifting conveyor 8 and is then delivered to a drag tion chamber 12 in which a ply 1s adapted to be burned, as` for example,

. doorways conveyor 9 whereby it is carried to a branch 10 of chute 1 and is mixed with the spent materials passing through 1 into preheater 2.

`A furnace 11 is provided with a combusa supply of oil fed through a feed pipe 13 to a burner 14. A grate 15 and regulating 16 are preferably provided to control admission of air to the combustion chamber. Kiln'feed chute 5 passes through chamber 12 and the' upper end of kiln 6 pro,-` ]ects into and communicates with this chamber, so that the heatedproducts of combustion must pass down kiln 6.

Y The discharge end lof kiln 6 and the feedend of preheater 2 project into a closed passage 17,- through which the gases discharged from kiln 6, pass-upward and then -into and through preheater 2. A chamber 18 comper end of chamber 17.

municating with passage 17 is preferably, but not necessarily, provided and has disposedtherein a' burner 19 for oil or other fuel. Feed chute 1 passes Fromthe upper end of 3 a. pipe -or flue 20 leads to an exhaust or suction fan 21 of `any well known construction and driverl by suit-r able means to exert a suction whichQdraws heater is driven off, and at the same time a' suitable fuel sup-` through the 'up- Q t found that known form of separator -23 in which the solid particles in the gases are separated and are passed through chute 24 back into chamber 3, while the gases themselves are forced out through flue 25 and pass into stack 26.

In operation and carrying out of the process, the spent filtering materials are prefer. ably broken and crushed into small particles if not in this form, and are then fed into preheater 2 through chute 1. v Burners 14 and 19are ignited, and preheater 2, crusher rolls 4, kiln 6, conveyors 7, 8 and 9, and fan 21 are set into operation. The suction due to fan 21 draws air vthroughthe doorways 16 and grate 15 of the furnace into chamber 12 where it supports ,combustion of fuel from burner 14, and is heated thereby. From chamber 12 theheated air and products of combustion are drawn into and through kiln6 parallel with the movement of the materials, through chamber 17, preheater 2 and then through Hue 20-to fan 21. As the heated gases pass through preheater 2, the moisture present in the spent materials passing continuously through the presubstantiaLportion of the more volatile refuse matter andother foreign substances in the spent filtering material are 'driven off. In this manner the drying and carbonization proceeds progressively until the massis discharged from the end of preheater into rolls 4, when the material is completely dried and the carbonization of the matter in the pores and cellsis substantially complete, the moisture and more volatile contents having been driven off in the preheater. Owing tothe amount of unconsumed combustible gases found present in the gases driven off in the preheater and kiln from the refuse, it is foundl desirable but not es sential to place a small flame from burner 19 in the chamber'18. A suflicient quantity of oxygen is found present in the gases to bonizing the organic matter 'or refuse.

Waste of `fuel is in -this manner prevented.

passing through the preheater, it is 'the materials have a. tendencyto form in lumps or balls. y these lumps, the mass is assed from the preheaterfthrough thecrus ing rolls 4 and- 1s again reducedto a relatively uniform and4 To break up 1gol support combustion of .these unconsumedl finely divided mass. F'rdm the crushing rolls, the heated mass yis passed through chute v5 and is dropped into the upperv end of kiln 6. As the kiln is inclined and rotating, the mass' will move tothe right in the figureand at the `same time will be turned over slowlyand agitated. 'l

The construction of furnace 11 and the relativeproportions of the grates are such that an excess of air over and above that requiredvto completely consume the fuel sup` plied through burner 14 is supplied, otherp wise no oxygen c ould be present in kiln 6 to burn out the refuse,and to support combustion at burner 19 in chamber 18.

The amountk of 'fuel supplied through burner 14 1s re lated so that the temperature of the com ustion chamber will be sufficiently high, and the air passing through the chamber will be heated to a temperature where the refuse' in the 'materials will be ignited when discharged into the upper end ofthe kiln from chute 5, but the temperature at the upper end of the kiln is maintained at a temperature below which fusion of the filtering materials will occur. VFor tainedl within the pores 'of the spent ymaterial as it is fed into the kiln, owing to the excess of oxygen supplied through the grate.

complete combustion of the fuel from urner 14, -together with the 4products of combustion is drawn through the kiln as shown by the dotted arrows a path parallel to the movement of the ignited mass due to' the powerful draft or suction created by fan 21. Combustion being continuously initiated as the materials are fed into the kiln, and the air drawn through ture at w ichv the'initial-combustion w11l be sustained,lthe heated air is drawn or forced into intimatev contact VLwith the ignitedma- -terials as'they'are turned over slowly and f advanced alon the kiln. The heat gens erated by the urning refuse is more than sufficient to sustain the combustion of the mass. The air is drawn around the particles and through the pores of the material, and the oxygen contained therein will cause the burning out of the refuse to the desired ex'` tent. In practical operation of the apparatusl disclosed the'temperature of ,the` kiln actually increasesas the burning material progresses through the kiln, and is highest at a point about three quarters along the The air, after being initially heated` 'in the flameand causin ate 15 being heated to a temperavlengthv of the kiln. This increase inl temperature along the `kiln is due solely to the urning of the refuse and all other fuel is chamber.

burned and consumed in the combustionV It will be noted' that a large volume of v air passes through the kiln without being drawn throught e pores of or contacting with' theparticles of the material being treated.I It will also be noted that the agitation of the mass-due tothe rotary movement of the kiln is relatively slow and that f* the major portion of the oxygen consumed 4in burnin out the refuse,` is drawn through .the mass y the powerful suction which is lthe main factor in propagating combustionthrou'gh the mass. The main function of agitatlon is to cnause the feeding of the materials through the kiln, and the aid to com bustion while important, is a subordinate function. For this reason no agitating members are used in the kiln, although such agitating members'may be used in order to increase the, agitation and thereby increase the capacity of the lant, by increasing the contacting action o the particles with the air.

The treated material passes through the kiln in the direction'shown by the full linev arrows and finally drops into conveyor 7'. Conveyor 7 moves the material rto vertical conveyor l8 Where a part of the hot material is picked u Aand delivered to a drag conveyor 9 -an is finally returned to chute 1 where .it is mixed with the spent materials z passing into .the dryerv for treatment. It is ound in practice that this tailing back of part of the hot revivified material substantially aids the drying operation. o

'The main portion of the revivified material is carried by conveyor 7 to a mixer where it lis properly mixed and prepared for further use. The details of the mixing operation form no part of the present invention, and the mixer has accordingly not been shown. Y

The heated gases from the2kiln are drawn upward'in'17, and the ltemperature is again raised tothe yignition point of the unconsumed combustible elements of theseheatedgases by the flame from burner 19. 'Ifhe gases then are drawn through dryer 2 with the donibustible elements burning, drying and preheating theA materials passin through the preheater as'above describe lf the heat lin the' gases is insufiicient for the preheating operation, more fuel may be supplid through 19. ,A y

Froml the preheater the gases are drawn through flue 20 by fan'21 and dlscharged 4into 4flue 22. Owing to the powerful draft from fan 21, a quantity of thecrushed particles .of the filtering material are carried in the gases. The gases are therefore pass hrough a separator or cyclone 25,` andthe entrained particles are removed being dis- -charged through flue 24 into chamber 3. The gases pass upwardk through flue 25 and out through the stack.

.Having described preferred 'forms of the invention, what is desired to be secured by Letters Patent and claimed as new isz- 1. In a continuous process for revivifying spentiiltering materials, the step of continuously initiating the combustion of the carbonaceous materials retained within the pores ofv successive unignited portions thereof.

2. In a continuous process for revivifying spent filtering material, the steps of continuously initiating the .combustion ofthe carbonaceous materials retained vwithin the pores .of successive unignited portions thereof, and propagating' the combustion thereof by the circulation of a combustion supporting fluid therethrough.

.3. In acontinuous process for revivifying spent filtering materials, the steps of con- .tinuously initiating the combustion of the 25 carbonaceous materials retained within the ing material which comprises passing the saine progressively vlengthwise through a heated zone in contact with combustion products emitted from a combustion'flame and contacting the'hot m-ass with a current of preheatedv combustion supporting gas.

6. The process as set forth in claim 5 in which the preheated-gases travel in parallel with the movement of the heated mass.

7. The herein described process of revivi- .fying s pent filtering materials which comprises initiating the combustion of organic impurities contained in the spentmaterials by` a flame, agitating the materials, and

`maintaining continued combustion of the organic impurities remaining the materi-alsby contacting the ignited mass with a `current of air.

8. The herein described process of revivifying spent kieselguhr which comprises drying the kieselguhr, allowing a flame to play upon the dried kieselguhr to cause combustion of' foreign matter in the kieselguhr, and continuously advancing the combustion of said foreign matter in the kieselguhr by subjecting the ignited mass 4of kieselguhr to a fluid medium containing oxygen While conveying the kieselguhr through a retort.

9. The herein described process of re.

vivifying lspent filtering materials which comprises preliminarily drying the materials, then allowing flame'to play upon the dried material to cause combustionof foreign matter contained thereimland contacting ,the ignited mass While, in motion with a current of air in a manner to propagate the combustion of' Iforeign matter throughout the mass.

-10. The herein described process of revivifying spent filtering materials which comprises a continuous feeding of spent material through two communicating retorts, drying the material in the first retort, allowing a fiame to play upon the dried material entering the second retort to cause an initial combustiony of the foreign matter contained therein, continuously advancing combustion of said foreign matter in the moving material in the second'retort by subjecting the ignitedmass to a Huid medium containing oxygen, and passing the products of combustion from the second retort through vthe first retort for preliminarily drying spent material passing through the first retort.

STANLEY HILLER. 

